A new video on the Disney Parks YouTube page shows how Imagineer Joe Herrington creates the sound for Radiator Springs Racers in Cars Land:
Each ride vehicle on Radiator Springs Racers is a moving mini-theater that delivers a show to our guests as they travel through the attraction. And — as with any theatrical experience — dialogue, music and sound effects play a key role in telling our story. Joe Herrington, Principal Media Designer for Walt Disney Imagineering, reveals how he’s helped design, record, edit and install a compelling audio track for our attraction.
http://www.youtube.com/watch?v=cKM3swRDFXE